Curious George

Hi, I am a newbie but my sub started humming for a while (several minutes) upon powering up so I decided to crack it open, mostly to satisfy my own curiosity. It's a different model (old PSB Subsonic 5i) but it does have the big yellow thingy that can be seen at the top of the first pic of the quoted posting, the one with the text printed on top "indigo xxxx Rev. B xxx". In fact I think it may be the same part. On mine, however, it seems to have leaked a brown resin like goo all around and there's some browning on the underside of the circuit board, presumably as a result of the ooze. My questions are, 1) what is this component called? 2) Is the brownish ooze indeed from the failure of this component? 3) If so, can I simply buy this component and replace it myself or am I biting off more than I can chew as someone who just knows how to simply solder things on a board? Any guidance would be greatly appreciated.